This invention relates to an instrument adapted to be inserted through an endoscope channel into the body cavity of the human being together with an endoscope and remove a foreign substance such as polyp, stone etc. outside of the body cavity of the human being.
A variety of foreign substance removing instruments are found in the art and in these instruments the head section of the instrument i.e., trap means for trapping the foreign substance such as a polyp is fixed to the forward end of the instrument body which is passed through an endoscope channel. When any foreign substance such as a polyp is found during the observation of the body cavity, it is removed away from the body cavity by a suitable resecting instrument and trapped by the trap means. When the foreign substance is removed outside of the body cavity, it is required that the endoscope per se be removed from within the body cavity of the human being. The endoscope channel is small enough to permit a slender body of the instrument to be passed therethrough and in contrast the foreign substance is relatively large in size. It is therefore impossible to withdraw the instrument from the endoscope channel with the foreign substance trapped by the trap means.
When a plurality of polyps are to be removed away from the body cavity for examination, the endoscope should be inserted into, and withdrawn from, the body cavity of the human being a corresponding number of times. It is not easy for the operator to insert the endoscope in proper place within the body cavity of the human being and such an operation imparts a severe pain to the patient. If, therefore, a plurality of polyps are to be removed outside the body cavity, a cumbersome operation is involved and the patient suffers from a pain while at the same time being exposed to a danger.